Leon sieieix



WUNBESBS 1 (No Model.) V

L. SIRIEIX. GORREGTING DEVICE FOR SHIPS OMPASSBS. No. 378,528.

-rTnn STATES PATENT Trice..

LON SIRIEIX, OF SAN FRANCISCO, CALIFORNIA, ASSIGNOR TO THE SIRIEIXMARINERS COMPASS COMPANY, OF CALIFORNIA.

CORRECTING DEVICE FOR SHIPS COMIPASSES.

SPECIFICATION forming part of Letters Patent No. 378,528. dated February28, 1888.

Application filed April 1G, 1887. Serial No. 235,116. (No model.)

To all whom, it may concern.:

Be it known that I, LEON Sinners., of the city and county of SanFrancisco, State of California, have discovered and invented an 5Improved Apparatus for Correcting the Deviations of the Magnetic Needleor Compass; and I do hereby declare that the following is a true andcorrect description thereof.

My invention has for its object the provision xo of a simple andeffective arrangement for correcting the deviations of the magneticneedle, whether such deviations arise from general or local influences.

It is well known that any local attractionsuch as the proximity of ironor loadstone will greatly disturb the normal position of the needle andproduce more or less deviation, according to the condition under whichthe needle is placed. rIhis is especially noticeable 2o on iron or steelvessels or ships, or where such magnetic bodies are carried by woodenvessels. In such cases the deviation of the magnetic needle is often sogreat` and uncertain as to render it almost useless as a guide tonavigation. I have discovered that this deviation can be corrected bymeans of a correcting compass provided. with certain magnetic bars, theprincipal ones o`f which are set or held transversely to theI length ofthe vessel, and

3o that the action of the magnetic current passing through these barswill correct the prime needle or compass, and that the power of thiscorrecting influence can be regulated by the vertical adjustment of theeorrectingcompass so as to produce a differential or differentiatedaction upon the needle of the prime compass, and also that by theaddition of inductors of soft iron placed at the poles of the correctingcompass all quadrantal deviation arising from .4o induction will becompensated and the action oi' the correcting-compass aided.

In this speciicvation I use the term differential77 to designate theposition which the needle assumes when caught between the two forcesderived, the one from the terrestrial magnetism and the other from thesub-perma nent and induced magnetism of the vessel..

.flhe accompanying drawings illustrate a practical means for carryingthe invention into 5o practice and use.

Figure l is a vertical section of the compass-box, showing the true orprime compass and the correcting-compass in position. Fig.

2 is a perspective view of the compass-box with a portion broken away toshow the magnetic inductors and their means for adjustment. Fig. 3 is abottom view of the prime compass. Fig. 4 is a plan view of the bottom ofthe compassvbox. Fig. 5 is a plan view of the upper card of thecorrector-compass, and 6o Fig. 6 is a bottom view of the same.

Let A represent the ease, binnacle, or box in which a compass ormagnetic needle, B, is mounted in the usual and ordinary Way. For thepurposes of brevity and perspicuity the compass B will be termed theprime conn pass throughout the speciiication.

I may divide the case, bi'nnicle, or box A by a horizontal partitioninto an upper and a lower compartment; or, if preferred, it may 7o haveonly a single compartment,in which the entire mechanism is placed andmounted.

IVhen the case7 binnacle, or box is divided into two compartments, theprime compass is mounted in the upper compartment and thecorrecting-compass and parts used with it in the lower compartment. Onthe under side of the prime-compass card B, I sccure'three parallelmagnetic bars, of steel or other magnetic metal, c d e, placed edgewise.The mid 8o dle bar, d, coincides eXactl y With the magnetic lineindicated on the face of the prime compass by N and S, while the bars cand e are parallel with it and equidistant from it on each side, thedistance being thirty degrees (300) from the middle bar. I have found inpractice that three bars thus arranged give better results than I canotherwise obtain, or have thus far obtained, and consequently I preferthe three arranged as described.

Upon the pointed upper end of a rod or spindle, K, which extends intothe box A and can be adjusted from the outside thereof, thecorrecting-compass is mounted beneath the prime compass.Thecorrecting-compassconsists of two disks of card-board, mica, or othernon-magnetic substance, the upper disk, Z,bel ing somewhat larger indiameter than the lower disk, Z. These disks are fixed on the centralhub or center pivot-block at a short 10o the vessel.

distance apart, as shown in Fig. 1, and are separated by three magneticbars, c c c,par allel with each other, and thirty degrees (30) from eachother, as above stated in relation to the bars on the prime compass, andfor the same reason. The middle bar, tZ,is somewhat heavier than theside bars, c e', and it is secured on a line corresponding with N and Son the face of the upper disk, Z. On the upper face of the disk Z, Isecure four pairsof narrow magnetic bars, n n, placed diagonally acrosseach other and across the disk, so that each pair of bars from thecenter to the periphery of the disk will point tov one of the cardinalpoints of the compass, the four pairs of cross bars or strips formingeight radial pairs leading from the center outward. The poles of thesesmall bars n n are arranged to balance each other, half north and halfsouth, as indicated in Fig. 5 by N and S.

Upon the bottom of the lower compartment of the binnacle or box I secureabrass or other non-magnetic bar, F, by means of a pivot at its middle,which pivot is preferably the rod K. To each end of the bar F is secureda short upright block of soft iron, G. A horizontal slot is made in theside of the case A opposite one of the blocks G, through which athreaded pin from the block passes, and a thumb or set nut, z', servesto fix the blocks and the connecting-bar F in place by tightening thenut against the outside of the case.v By loosening the nut the bar F,with its blocks G G, can be adjusted a distance equal to the length ofthe slotin-order to put them in the line of the induced magnetism. Eachof the blocks G has the edge of its inner face beveled, so as to presenttwo narrow blunt edges, j j, toward the middle of the bar. Thecorrecting-compass Z Z is held in place between the blocks G G by meansof guides or stops r r, so that the magnetic bars c d e are settransversely to the length of the ship, while their polescoincide indirection with the blocks G G. The guides or stops r rare nonmagnetic,and the arrangement is such that the correcting-compass can be freelyadjusted vertically, and will be allowed a slight rotary movement tofeel its true position in respect to the parts G G.

In practice the case, binnacle, or box A is so placed that the soft-ironblocks G G are on the sides of the correctingcornpass next to the sidesof the vessel. The soft-iron blocks G will then be induced by thesub-permanent magnetism of the iron sides of the ship. The blunt inneredge of the block on one side will be a negative pole and the inner edgeof the opposite block will be a positive pole, according to the positionof the magnetic poles of The correcting compass being mounted betweenthe two blocks G G, with liberty for some rotation, the center bar, d',will arrange itself exactly opposite the poles of said blocks; and thisgreat certitude and nicety of position is insured by the parallel flatbars an on the upper face of disk Z. These bars compensate the magneticinfluence and enable me to reach an exactness of position which I cannotvotherwise obtain, as I have found in my experiments that the employmentof these bars in the manner described corrects the compass to a greatnicety and compensates several degrees of deviation which wouldotherwise affect the needle.

With the correcting-compass mounted as described the prime compass willbe found to be completely corrected and deviations compensated for in amanner to render the prime compass a reliable indicator and guide fornavigation. I have found that good effects are also produced in caseswhere it is desired to counteract or correct the magnetic influence ofvertical iron on a vessel by the employment of two blades of soft iron,P, united by a nonmagnetic strip or bar, M, in the box or compartmentcontaining the correcting-compass. The strip M is set transversely tothe bar F fore and aft. 'Ihese supplemental inductors l? l? are onlyneeded where there is a great quantity of induction from vertical iron,and in other cases they may be omitted.

rIhe combined action of the correcting-compass and. the soft-iron blocksG,which act as inductors, is to correct the deviations due to bothsub-permanent and induced magnetism of the ship. The constant deviationis compensated by the vertical adjustment of the correcting-compass, andthe allowance for the changes of magnetic latitude and magneticlongitude is made in the same way, said changes as well as the constantdeviation being ascertained in the usual way by observations. Thesemicircular deviation is compensated by the soft-iron blocks G, inconjunction with the magnetic bars on the correcting-compass, theinductors G being influenced by the magnet ism from the ships sides andin turn influencing the main bar d of the correcting-compass, and thequadrantal deviation is corrected by the softiron blocks orinductors,which, according to natural laws governing the induction ofsoft iron, change their polarity as the ships course is changed inazimuth, in correspondence with the changes of polarity of the inducedmagnetism of the ships sides. The heeling error is corrected or overcomeby the construction and arrangement of the prime and correctorcompasses, by means of which they are held always parallel with eachother; and, so far as my experiments and tests have demonstrated, thisdifculty of the heeling error will not manifest itself to anyappreciable extent in my compass. If it should, it can readily becorrected in the usual manner well known to seamen.

Having thus described my invention,what I claim, and desire to secure byLetters Patent, 1s-

1. A correcting-compass, ZZ', provided with two sets of magnetic bars,one set being'underncath the card of the compass and the other IOO IIO

set on its top, in combination with a prime compass having magneticbars, substantially as specified.

2. In a compensating compass, the combination, with a prime compass anda correcting-compass,of the soft-iron blocks G,mounted beside and movedwith the correctingvcompass, as set forth.

3. In a compensating compass, the combination, with a prime compass anda correctingcompass, of the soft-iron blocks G, mounted beside and movedwith the correcting-com pass, and means, substantially as described, foradjusting the said blocks and correctingcompass in a horizontal plane,as set forth.

4. In a compensating compass, the combination, with the prime compassand a correcting-compass, of the soft-iron blocks G G, and bar F, on theends of which they are mounted, and the guides or stops r r on bar F, tohold zo the correcting-compass within slight limits of rotation, as setforth.

5. In a compensating compass, the combination of a prime and acorrecting compass, and the upright soft-iron blades P, arranged 25relatively to the correcting-compass, as described, to compensate themagnetism from vertical iron, substantially as specified.

In Witness whereof I have hereunto set my hand.

LEON sIRIEiX. Vitnesses:

E. P. VoIsARD, J. J. ScRrvNnR.

